EWMA Weight Smoothing: Overcoming Low-Carb Water Noise
How 10-day exponential smoothing from The Hacker's Diet reveals genuine fat loss.
One of the most psychologically damaging aspects of weight management is the daily scale fluctuation. A dieter eats strictly on-plan for four consecutive days, steps on the scale on Friday morning, and sees an inexplicable 0.8kg jump. Despair follows, diets are abandoned, and confidence crumbles. Almost all of this noise is water.
1. The 1:3.7 Glycogen-Water Ratio
Every gram of glycogen stored in human liver and skeletal muscle tissue binds approximately 3 to 4 grams of water. When you transition into nutritional ketosis, liver glycogen depletes rapidly, flushing 1.5kg to 3kg of bound water weight within the first 72 to 96 hours.
Conversely, a single meal with higher sodium or temporary digestive retention can cause your body to hold 1kg of fluid without a single gram of new adipose tissue being formed. Daily scale weight is 80% fluid and digestive noise.
2. John Walker's 10-Day EWMA Filter
In 1988, Autodesk founder John Walker published The Hacker's Diet, applying classical signal processing to human weight logs. He demonstrated that human weight behaves like a noisy electrical signal with an underlying low-frequency trend.
Repast applies a 10-day Exponentially Weighted Moving Average (EWMA) filter with alpha = 0.10: Today's Smoothed Trend = (0.10 × Today's Scale Reading) + (0.90 × Yesterday's Smoothed Value). Transient fluid spikes are mathematically dampened, exposing genuine weekly adipose loss.
Never judge dietary adherence by a single morning weigh-in. Track the 10-day EWMA trend line to see reality.
Filter daily water weight noise with native EWMA.
Track genuine adipose reduction with built-in exponential smoothing (alpha = 0.10). No panic, no false plateaus.
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